Measurement of accelerated plasma in plasma focus by laser differential interferometry methods

Summary Form only given, as follows. The run-down phase of the discharge in a plasma focus device was studied by means of differential interferometry. The dynamics and the structure of the plasma sheath were measured with an interferograph under different hydrogen gas pressures. The relation between X-ray yield and the sheath structure was studied. The experimental results show that in the rundown phase of the discharge there is a clear plasma sheath. The thickness of sheath increases with filling gas pressure (15.5 approximately 5 torr). When the pressure reaches 5.0 torr the sheath back cannot be distinguished clearly. The X-ray yield decreases as the thickness of the plasma sheath increases. The yield is very small when there is a disturbance behind the sheath front. Between 1.5 and 5.0 torr filling pressure, the velocity of the sheath is about 5.5*10/sup 6/ cm/s.<>